package command

import (
	"bytes"
	"flag"
	"fmt"
	"io"
	"strings"
	"text/tabwriter"

	"github.com/hashicorp/consul/api"
	"github.com/mitchellh/cli"
)

// KVGetCommand is a Command implementation that is used to fetch the value of
// a key from the key-value store.
type KVGetCommand struct {
	Ui cli.Ui
}

func (c *KVGetCommand) Help() string {
	helpText := `
Usage: consul kv get [options] [KEY_OR_PREFIX]

  Retrieves the value from Consul's key-value store at the given key name. If no
  key exists with that name, an error is returned. If a key exists with that
  name but has no data, nothing is returned. If the name or prefix is omitted,
  it defaults to "" which is the root of the key-value store.

  To retrieve the value for the key named "foo" in the key-value store:

      $ consul kv get foo

  This will return the original, raw value stored in Consul. To view detailed
  information about the key, specify the "-detailed" flag. This will output all
  known metadata about the key including ModifyIndex and any user-supplied
  flags:

      $ consul kv get -detailed foo

  To treat the path as a prefix and list all keys which start with the given
  prefix, specify the "-recurse" flag:

      $ consul kv get -recurse foo

  This will return all key-vlaue pairs. To just list the keys which start with
  the specified prefix, use the "-keys" option instead:

      $ consul kv get -keys foo

  For a full list of options and examples, please see the Consul documentation.

` + apiOptsText + `

KV Get Options:

  -detailed               Provide additional metadata about the key in addition
                          to the value such as the ModifyIndex and any flags
                          that may have been set on the key. The default value
                          is false.

  -keys                   List keys which start with the given prefix, but not
                          their values. This is especially useful if you only
                          need the key names themselves. This option is commonly
                          combined with the -separator option. The default value
                          is false.

  -recurse                Recursively look at all keys prefixed with the given
                          path. The default value is false.

  -separator=<string>     String to use as a separator between keys. The default
                          value is "/", but this option is only taken into
                          account when paired with the -keys flag.

`
	return strings.TrimSpace(helpText)
}

func (c *KVGetCommand) Run(args []string) int {
	cmdFlags := flag.NewFlagSet("get", flag.ContinueOnError)
	cmdFlags.Usage = func() { c.Ui.Output(c.Help()) }
	datacenter := cmdFlags.String("datacenter", "", "")
	token := cmdFlags.String("token", "", "")
	stale := cmdFlags.Bool("stale", false, "")
	detailed := cmdFlags.Bool("detailed", false, "")
	keys := cmdFlags.Bool("keys", false, "")
	recurse := cmdFlags.Bool("recurse", false, "")
	separator := cmdFlags.String("separator", "/", "")
	httpAddr := HTTPAddrFlag(cmdFlags)
	if err := cmdFlags.Parse(args); err != nil {
		return 1
	}

	key := ""

	// Check for arg validation
	args = cmdFlags.Args()
	switch len(args) {
	case 0:
		key = ""
	case 1:
		key = args[0]
	default:
		c.Ui.Error(fmt.Sprintf("Too many arguments (expected 1, got %d)", len(args)))
		return 1
	}

	// This is just a "nice" thing to do. Since pairs cannot start with a /, but
	// users will likely put "/" or "/foo", lets go ahead and strip that for them
	// here.
	if len(key) > 0 && key[0] == '/' {
		key = key[1:]
	}

	// If the key is empty and we are not doing a recursive or key-based lookup,
	// this is an error.
	if key == "" && !(*recurse || *keys) {
		c.Ui.Error("Error! Missing KEY argument")
		return 1
	}

	// Create and test the HTTP client
	conf := api.DefaultConfig()
	conf.Address = *httpAddr
	conf.Token = *token
	client, err := api.NewClient(conf)
	if err != nil {
		c.Ui.Error(fmt.Sprintf("Error connecting to Consul agent: %s", err))
		return 1
	}

	switch {
	case *keys:
		keys, _, err := client.KV().Keys(key, *separator, &api.QueryOptions{
			Datacenter: *datacenter,
			AllowStale: *stale,
		})
		if err != nil {
			c.Ui.Error(fmt.Sprintf("Error querying Consul agent: %s", err))
			return 1
		}

		for _, k := range keys {
			c.Ui.Info(string(k))
		}

		return 0
	case *recurse:
		pairs, _, err := client.KV().List(key, &api.QueryOptions{
			Datacenter: *datacenter,
			AllowStale: *stale,
		})
		if err != nil {
			c.Ui.Error(fmt.Sprintf("Error querying Consul agent: %s", err))
			return 1
		}

		for i, pair := range pairs {
			if *detailed {
				var b bytes.Buffer
				if err := prettyKVPair(&b, pair); err != nil {
					c.Ui.Error(fmt.Sprintf("Error rendering KV pair: %s", err))
					return 1
				}

				c.Ui.Info(b.String())

				if i < len(pairs)-1 {
					c.Ui.Info("")
				}
			} else {
				c.Ui.Info(fmt.Sprintf("%s:%s", pair.Key, pair.Value))
			}
		}

		return 0
	default:
		pair, _, err := client.KV().Get(key, &api.QueryOptions{
			Datacenter: *datacenter,
			AllowStale: *stale,
		})
		if err != nil {
			c.Ui.Error(fmt.Sprintf("Error querying Consul agent: %s", err))
			return 1
		}

		if pair == nil {
			c.Ui.Error(fmt.Sprintf("Error! No key exists at: %s", key))
			return 1
		}

		if *detailed {
			var b bytes.Buffer
			if err := prettyKVPair(&b, pair); err != nil {
				c.Ui.Error(fmt.Sprintf("Error rendering KV pair: %s", err))
				return 1
			}

			c.Ui.Info(b.String())
			return 0
		} else {
			c.Ui.Info(string(pair.Value))
			return 0
		}
	}
}

func (c *KVGetCommand) Synopsis() string {
	return "Retrieves or lists data from the KV store"
}

func prettyKVPair(w io.Writer, pair *api.KVPair) error {
	tw := tabwriter.NewWriter(w, 0, 2, 6, ' ', 0)
	fmt.Fprintf(tw, "CreateIndex\t%d\n", pair.CreateIndex)
	fmt.Fprintf(tw, "Flags\t%d\n", pair.Flags)
	fmt.Fprintf(tw, "Key\t%s\n", pair.Key)
	fmt.Fprintf(tw, "LockIndex\t%d\n", pair.LockIndex)
	fmt.Fprintf(tw, "ModifyIndex\t%d\n", pair.ModifyIndex)
	if pair.Session == "" {
		fmt.Fprintf(tw, "Session\t-\n")
	} else {
		fmt.Fprintf(tw, "Session\t%s\n", pair.Session)
	}
	fmt.Fprintf(tw, "Value\t%s", pair.Value)
	return tw.Flush()
}
